On Tue, 7 Feb 2006, William Chops Westfield wrote:

> On Feb 7, 2006, at 1:17 PM, Peter wrote:
>
>>> But really, a circuit like that hooked up to
>>> a serial port with the clock derived from a one-shot...
>> 
>> How about two phototransistors suction cupped to the monitor
>> screen and a program to flash two rectangles in the right seuqence ?
>
> I had a remarkably similar thought myself, although I was going
> to use CDS photocells...  We're all sick.
>
> Maybe we should just do it?  It probably takes at least 3 signals,
> doesn't it?

2 are enough as you need a power/run/program switch anyway, and that can 
handle the power/vpp sequencing. Please read my other posting about 
flicker and low pass.

On the other hand, making a contraption using perforated (on 2 tracks) 
video tape (removed from cassette) and a hand crank should work fine. 
The tape has two tracks, one for clock, one for data, and the data holes 
must be smaller (or registered later than the relevant clock edge).

Peter
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist